Seismic tie beams and strap footing 1

[RamiHabchi93]

Hi
I have an eccentric footing,I need to connect it to a strap footing.and also I need to connect footings with seismic tie beams.
If for e.g seismic tie beams should be designed for axial force=10% column load.
Should I design the strap footing as a column under the 10% axial force and bending moments from eccentric footing at the same time? Or should I connect the eccentric footing to a seismic tie beams and a strap footing.thank u

 

[KootK]

I think that it would be correct, and most efficient, to use the strap footing for both purposes.

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.

 

[RamiHabchi93]

Thank u
The problem is that aci limits seismic tie beam's least dimension to a maximum of 18 inches.I don't know the reason behind this limitation but it makes me think that adding flexure to the beam might lead to another limitation that I ignore.

 

[bones206]

18 inches is not a mandatory limit. You can make it wider if you want to.

If I understand your situation correctly, your grade beam design should envelope the requirements for seismic ties as well as the requirements for grade beams subject to flexure.

 

[KootK]

I agree with bones. The clause doesn't say shall not exceed 18". Instead it says need not exceed 18". In computer speak:

Least Dimension = MIN [18", [clear column spacing / 20]]

I like to debate structural engineering theory -- a lot. If I challenge you on something, know that I'm doing so because I respect your opinion enough to either change it or adopt it.